Erica spp. and Calluna spp., AIR-i-ka and ka-LOON-a
A few to many weeks depending on cultivar and care. For example, C. vulgaris 'Carmen', 'Darkness', 'Silver Knight' and 'Spring Cream' lasted from 2-4 weeks under reasonable interior conditions while 'Cuprea' and 'Marleen' lasted nearly 12 weeks.
At 34-38 F, many cultivars can be stored for 1-3 weeks or longer.
Calluna is Greek; to sweep as the branches are sometimes used as brooms. Erica is Greek from “ereike” (heather) and “ereiko” (to break), an infusion from the leaves was reputed to break bladder stones.
These two species are often confused. The main way to tell them apart is that with Erica, the calyx (outer part of flowers consisting of the sepals) is shorter than the corolla (inner circle of flower consisting of the petals) whereas with Calluna, the calyx is longer than the corolla.
Will generally do well in light levels at least bright enough to read a newspaper in comfort but more light would be better. Supplemental lighting is not always advantageous, depending on cultivar.